现代黄河三角洲表层沉积物的空间分布特征

发布时间：2018-01-10 10:35

本文关键词：现代黄河三角洲表层沉积物的空间分布特征　出处：《海洋地质与第四纪地质》2016年02期 　论文类型：期刊论文

【摘要】：基于近期在黄河三角洲附近海域采集的97个表层沉积物样品的粒度测试结果,研究了黄河三角洲海域表层沉积物的类型和空间分布特征,探讨了沉积物粒度分布特征与物源和沉积动力环境之间的关系。研究结果表明,研究区表层沉积物类型以砂质粉砂和粉砂为主,在绝大部分海域,表层沉积物的偏态表现为正偏和极正偏,分选程度较差,峰态表现为宽和很宽。现行河口三角洲叶瓣周围的表层沉积物以砂质粉砂为主,粒度较粗;而在远离河口的区域表层沉积物以粉砂为主,粒度较细。与20世纪80年代的观测结果相比,受物源供应和沉积环境的共同影响,近期黄河三角洲沿岸的表层沉积物有粗化的趋势,且河口口门区域表层沉积物粗化趋势最为明显。表层沉积物粒度粗化的主要原因是黄河入海泥沙供应不足,导致三角洲沿岸侵蚀加剧;黄河调水调沙以来入海泥沙的粒度变粗,粗颗粒组分在河口口门附近快速堆积。黄河水下三角洲现代沉积速率的分布特征表明,黄河入海沉积物主要在现行河口及三角洲的近岸区域沉积,在15m以深的区域沉积速率较低。同时,还可看出入海泥沙有向北和东北向的运移趋势,与渤海中部泥质沉积以及通过莱州湾向渤海海峡的泥沙输运相对应。粗颗粒沉积物在现行河口三角洲叶瓣的堆积范围与潮流切变锋的位置基本一致,反映了物源供应和沉积动力环境对研究区表层沉积物分布特征的控制性影响。
[Abstract]:Based on the granularity test results of 97 surface sediment samples collected recently in the Yellow River Delta, the types and spatial distribution of surface sediments in the Yellow River Delta were studied. The relationship between sediment granularity distribution characteristics, provenance and sedimentary dynamic environment is discussed. The results show that the main types of surface sediments in the study area are sandy silt and silt, and in most of the sea area. The surface sediments show positive deviation and extreme positive deviation, and the separation degree is poor, and the peak state is wide and wide. The current surface sediments around the delta leaf flap are mainly sandy silt with coarse grain size. In the area far away from the estuary, silt is the main surface sediment with fine grain size. Compared with the observed results in 1980s, it is affected by the source supply and sedimentary environment. In recent years, the surface sediments along the Yellow River Delta have a trend of coarsening, and the trend of surface sediment coarsening is the most obvious in the estuary mouth area. The main reason for the coarsening of surface sediments is the insufficient supply of sediment from the Yellow River to the sea. Causes the delta coastal erosion to intensify; Since the Yellow River transferred water and sediment, the grain size of the sediment has become coarser, and the coarse particles have accumulated rapidly near the mouth of the estuary. The distribution characteristics of the modern sedimentation rate in the Yellow River underwater delta show that the sediment size is coarse. The sediment of the Yellow River entering the sea is mainly deposited in the current estuary and the near shore of the delta, and the deposition rate is lower at the depth of 15 m. At the same time, it can be seen that the sediment of the Yellow River entering the sea is moving northward and northeastward. Corresponding to the muddy deposits in the central Bohai Sea and the sediment transport from the Laizhou Bay to the Bohai Strait, the accumulation range of coarse grain sediments in the current estuarine delta lobes is basically consistent with the position of the tidal shear front. It reflects the controlling effects of source supply and sedimentary dynamic environment on the distribution characteristics of surface sediments in the study area.
【作者单位】：中国海洋大学海洋地球科学学院海底科学与探测技术教育部重点实验室;中国地质调查局青岛海洋地质研究所;
【基金】：国家自然科学基金项目(41376096;41376079) 中国地质调查项目(GZH200900501)
【分类号】：P736.21
【正文快照】： 海洋沉积物的粒度特征是现代海洋沉积学研究的重要指标之一,是沉积物在搬运、沉积以及再分配等过程的集中体现,蕴含着沉积物物源、海平面变化、水动力条件、搬运距离等诸多环境信息[1-4]。通过对沉积物粒度特征的研究,可以判定沉积物的输运方式,反演影响沉积物粒度变化的环境

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